See chapter 5, page 53, for the location of the setting you want to change.
After Power Loss. Default is Power Off ■ Power off—causes the computer to remain powered off when power is restored. ■ Power on—causes the computer to power on automatically as soon as power is restored. ■ Previous state—causes the computer to power on automatically as soon as power is restored, if it was on when power was lost
Which key should I press if I will have on settings "Power On from Keyboard Ports (enable/disable)" ?
There is written:
"When enabled, this feature allows a key press to power on the system when it is off (S5 state). If using a USB keyboard, it must be plugged into one of the rear ports labeled with the keyboard icon. Default is disable"